This invention relates to the balancing of turbine rotors in gas turbine engines, and, more particularly, to boltless balance weights for rotor disks of such engines.
Gas turbine engines include one or more rotors comprising a disk carrying a plurality of airfoil-shaped turbine blades which extract energy from combustion gases. Because of the high rotational speeds of the disks and the large disk and blade masses, proper balancing of the rotors of the turbine is important. Unbalance may, in some cases, seriously affect the rotating assembly bearings and engine operation.
One known method of balancing a rotor disk is to provide the disk with dedicated balance planes incorporating extra material. These can be selectively ground away as needed. However, this process is difficult to implement efficiently and with repeatable results.
Another known method for balancing turbine disks is to add washers or other weights to select bolted joints of the rotors. The number, position, and mass of the weighted washers needed to balance the disk is dependent on the balance characteristics of each turbine disk being balanced. These balance characteristics are determined by a balance test on each rotor. After finding the unbalance of a turbine rotor, the weighted washers are added to designated bolted joints until the rotor is balanced. While this method works well for turbine rotors with bolted joints, not all turbine rotors have such joints.